Have you ever had anyone tell you that they feel the "good kind of tired" while you are feeling the much-more-common bad kind of tired? How do you experience having a good appetite versus just being hungry? To put in scientific terms, how do we judge valence? »5/12/14 8:20am 5/12/14 8:20am

When we're born, the part of our brain that controls our most complex cognitive functions, such as self-awareness and creativity, isn't fully formed yet. It then starts developing very quickly...and much the same happens with chimpanzees. »8/11/11 5:30pm 8/11/11 5:30pm